With many services and resources now available over public networks, there is an increased need to provide strong authentication for those services or resources. Strong authentication, also referred to as two-factor authentication or multi-factor authentication, is defined as validation of two or more of three possible factors of authentication.
Such factors of authentication include something you know, something you have and something that you are. For example, a password may be something that you know. A key, physical token, mobile phone or device, among other objects may be something you have. Fingerprints, retinal scans, DNA, facial characteristics, among other options, may be something that you are.
A number of strong authentication mechanisms now rely on a mobile device as the physical factor of authentication. In particular, the mobile device is “something you have”.